Garden Canyon is a good Sierra Vista-area stop for hiking, picnicking, birdwatching, and rock art. The road into the canyon leads to fenced Apache and Hohokam pictograph sites, so the archaeological interest is easy to find without turning the visit into a difficult backcountry search.
The canyon sits in the Fort Huachuca area, so check access rules before setting out. Go for the desert mountain scenery as much as for the pictographs.